1865.] DUKE OF ARGYLL NATURAL SELECTION, 33 



of differences for mere variety or beauty. It may be con- 

 fidently said that no tribe of plants presents such grotesque 

 and beautiful differences, which no one until lately, conjectured 

 were of any use ; but now in almost every case I have been 

 able to show their important service. It should be re- 

 membered that with humming-birds or orchids, a modification 

 in one part will cause correlated changes in other parts. I 

 agree with what you say about beauty. I formerly thought 

 a good deal on the subject, and was led quite to repudiate the 

 doctrine of beauty being created for beauty's sake. I demur 

 also to the Duke's expression of " new births." That may be 

 a very good theory, but it is not mine, unless indeed he calls 

 a bird born with a beak yJoth of an inch longer than usual 

 " a new birth ; " but this is not the sense in which the term 

 would usually be understood. The more I work, the more I 

 feel convinced that it is by the accumulation of such extremely 

 slight variations that new species arise. I do not plead guilty 

 to the Duke's charge, that I forget that natural selection means 

 only the preservation of variations which independently arise.* 

 I have expressed this in as strong language as I could use, 

 but it would have been infinitely tedious had I on every 

 occasion thus guarded myself. I will cry " peccavi " when I 

 hear of the Duke or you attacking breeders for saying that 

 man has made his improved shorthorns, or pouter pigeons, or 

 bantams. And I could quote still stronger expressions used 

 by agriculturists. Man does make his artificial breeds, for his 

 selective power is of such importance relatively to that of the 

 slight spontaneous variations. But no one will attack breeders 

 for using such expressions, and the rising generation will not 

 blame me. 



Many thanks for your offer of sending me the ^Elements.' t 



* " Strictly speaking, therefore, failure of such new forms as [may 



Mr. Darwin's theory is not a theory be born into the world." Scots- 



on the Origin of Species at all, but man, Dec. 6, 1864. 

 only a theory on the causes which f Sixth edition in one volume, 

 lead to the relative success and 



VOL. III. D 



